Question
Please help me solve this problem?!?!
Find the first six terms and the sixth partial sum of the sequence whose nth term is
an = 5n2 − n.
a1 =
a2 =
a3 =
a4 =
a5 =
a6 =
S6 =
Find the first six terms and the sixth partial sum of the sequence whose nth term is
an = 5n2 − n.
a1 =
a2 =
a3 =
a4 =
a5 =
a6 =
S6 =
Answers
Steve
well, finding the first six terms is easy, right?
An = 5n^2-1, so here's a table:
n An
1 5*1^2-1 = 5-1 = 4
2 5*2^2-2 = 20-2 = 18
3 5*3^2-3 = 45-3 = 42
4 5*4^2-4 = 80-4 = 76
5 5*5^2-5 = 125-5 = 120
6 5*6^2-6 = 180-6 = 174
Now just add 'em up to get S6
An = 5n^2-1, so here's a table:
n An
1 5*1^2-1 = 5-1 = 4
2 5*2^2-2 = 20-2 = 18
3 5*3^2-3 = 45-3 = 42
4 5*4^2-4 = 80-4 = 76
5 5*5^2-5 = 125-5 = 120
6 5*6^2-6 = 180-6 = 174
Now just add 'em up to get S6